It is frequently necessary to locate and support a workpiece in a determined position and orientation so that an operation can be effected thereon, particularly an operation which applies pressure to the workpiece, which pressure must be absorbed and resisted by the workpiece support means without causing damage to the workpiece. It may well be necessary to support the workpiece at several locations to prevent it distorting under the force applied to it by the operation.
The invention has particular although not exclusive application to support means for printed circuit boards to form electronic circuits during a printing operation thereon, which circuit boards may already include, on a face thereof opposite to the face which is to be printed, circuit components which project from the face of the board.
Since the board may be of considerable size, for example 500 mm square and relatively thin, It cannot be supported merely by its edges on spaced supports of a conveyor, but must be supported, when at a printing position, by support means applied to the underside of the board or to projections on the underside of the board at positions intermediate the edges. Forming a shaped support member to support the board at determined positions and at determined heights at such positions can be a very time consuming operation which is very uneconomic when there is only to be a short print run.
It is also desirable to provide means to secure a board in position against upward movement. Vacuum suction has been proposed but is unsatisfactory particularly when the underside of the board to which vacuum means must be applied is not smooth, for example it may have components thereon, or if the board includes through holes such as those intended to receive wires to connect components.